Watts of LED per square area needed for growing orchids?

[daemondamian]

TLDR: how many watts of LED per square area is needed for growing low to moderate light loving orchids?

I have an orchid growing area of 213cm length x 47cm width by 126cm high for low light growing species such as masdevallias, draculas, stellis, pleurothallis, paphiopedilums,oncidiums, gongoras etc as seen in the photo below.



Although it receives some natural lighting, it is reduced if I have to put the blinds down to block out direct sun and associated heat on hot days and possibly in winter (I just moved in, in Summer).

I was thinking of possibly using LED lights as they put out less heat and last longer. In particular I found: Ledvance LED Panel 32W (1200 x 300mm) - Tri Colour

New Tri Colour LED Panel Light 32W with 5 Year Warranty

and: Osram LED Panel 32W (1200 x 300mm) - Daylight 6500K

Osram Ledvance LED Panel Troffer 32W - 1200mm x 300mm

which could be suspended via these kits:
Osram Ledvance LED Panel Troffer Wire Suspension Kit


Having previously grown orchids and other plants in 3ft x 40cm areas - as well running 3ft freshwater planted aquariums - where I used up to 120W of fluorescent lighting, 30W doesnt seem like it would hardly be sufficient *but* it is LED so does that make a difference or is there a watt per area squared that I should be aiming for regardless of lightbulb type?